This gun is almost certainly numbered, so you're probably either missing a number in an out-of-the-way place, or you're confusing the s/n as an address or as part of a proof mark. English guns will normally have the s/n on the receiver (sometimes on a tang), on the barrels, and on the iron of the forearm, so you could be sure that the parts would all fit together if multiple guns were transported together. A pic of the water table would let us know when and where it was proofed, and the company name and address would also give a clue as to when it was produced.

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